Cleaning process



Patented Sept. 17, 1929 UNITED STATES ARTHUR EDWARD HATFIELD, OF LEYTON STONE, AND EUSTACE ALEXANDER ALLIO'IT,

PATENT OFFICE OF GREENIBANK, CHESHAM BOIS, ENGLAND CLEANING rRooEss No Drawing. Application filed June 24, 1927, Serial No. 201,277, and in Great BritainEebruary 15, 1927.

Our invention relates to cleaning processes and more particularly to cleaning processes for use in dry cleaning, laundry Washing, wool scouring by means of solvents, and the 6 like. The invention is especially useful in connection with a process of the above type which is carried on in a continuous cyclic manner.

In Patent No, 1,704,604, granted to Arthur 10 Edward Hatfield (one of the joint inventors in the present case) on March 5, 1929, there is disclosed a process for clarifying and dehydrating the soiled solvent of Washing machines used for dry cleaning wherein a filter aid consisting of finely divided porous cellular silica is added to the soiled solvent and passed to a filter. The filter aid adsorbs dirt and moisture from the soiled solvent while 2 being carried in suspension and also after 0 being deposited upon the filter. The process described is a continuous cyclic process.

Further experimentation resulted in Pat-- ent N 0. 1,713,317, which was granted to the present inventors jointly on May 14th, 1929. This patent is directed to varying the rate at which filter aid is added to the soiled solvent to correspond with the amount of foreign matter in the soiled solvent as the process so proceeds.

Following this the present inventors developed a soap of high solubility and emulsifying power having little tendency to disassociate, and filed jointly patent application Serial No. 198,300 on June 11, 1927, directed to this dry cleaning soap. In the last named application there is disclosed a soap which is manufactured by saponifying a fatty acid of which the settin point is below 60 Fahrenheit with an a kaline solution and incorporating therewith an organic volatile liquid solvent as a stabilizing agent. More specifically the soap may comprise oleic acid from 99.5 per cent to 100 per cent pure,

which has been saponified with an aqueous manufactured from other ingredients.

solution of ammonia or with the carbonates of hydroxides of potassium or sodium, and with which cyclohexanol has been incorporated as a stabilizing agent. However, we do not limit ourselves to soaps containing these particular ingredients, as soaps of high solubility and emulsifying power having little tendency to dissociate may be This soap was not invented primarily for use in the processes disclosed in the above mentioned prior patents.

We have now discovered an improved process wherein both the filter aid disclosed in the aforesaid Patent No, 1,704,604 and the soap disclosed in the aforesaid patent application Serial No. 198,300, may be employed in conjunction to effect an improved result. According to the present process a soap such as those disclosed in co-pending application Serial No. 198,300 is added to a cleaning fluid in a washing machine, the soiled articles are washed therein and the soiled cleaning fluid and soap are withdrawn from the Washing machine and passed to a filter. A filter aid comprising finely divided cellular silica of low specific gravit (preferably a filter aid such as is disclose in Patent No. 1,704,604) is added to the soiled fluid between the washing machine and the filter and adsorbs dirt and moisture from the soiled fluid between the washing machine and the filter. The filter aid also adsorbs dirt and moisture from the soiled fluid after being deposited upon the filter. I

The soaps hitherto employed in the washing machines used for dry cleaning, laundry washing, etc, have been imperfectly soluble and have had a tendency to disassociate. A clogging effect has thereby been imposed upon the filter press on account of the disassociated soap which is caught therein and which tends normally to form an impermeable membrane or deposit in addition to that formed by the dirt and impurities alone. When ordinary kinds of filter aid are used this deposit, together with the emulsion of associated dirt. and other matter tends to slow the filtration unduly and eventually mtg stop it at an uneconomical stage.

y means of the type of soap which has been described and the type of filter aid to which reference has been made, we efl'ect quite a different process. The soap is entirely dissolved in the cleaning fluid and does not form a film around the particles of fore.

filter aid when they are added to the soiled solvent. The filter aid adsorbs dirt, impurities and moisture while carried in suspension between the washing machine and the filter, which has never been efl'ected be- In other words, the filter aids have only to deal with the foreign matters which must be removed from the cleansing fluid and are not hampered by the presence of disassociated or undissolved soap. Finally, the soap does not form an impermeable membrane or deposit additional to that formed by the dirt or impurities alone upon the filter.

It is thus possible to carry on a process which is truly continuous and cyclic.

As an example of how the invention may be carried out in practice the following (to which example the invention is not limited) may be taken.

Example A quantity of material which is to be cleaned is placed in a dry cleaning machine of known type having a cage divided into compartments, working under 10 to 20 inches vacuum, and adapted to be run as a hydro-extractor on completion of the washing operation. A suitable quantity of cleaning fluid is run into the machine, and suficient cleaning fluid over and above this to fill the pump and filter press and pipe lines connected therewith. Suflicient soap of the high solubility described, preferably a soap which is soluble in dry cleaning fluid described in Example No. 3 of applicants copending application Serial No. 198,300 is added. A convenient amount of this soap in concentrated form will be about 0.001% or less of the total amount of dry cleanin fluid employed, but this must be distribute over the days work to maintain a comparatively constant effect throughout the day. This liquid is sucked from the washer to a pump, which delivers it to a filter press from which the clear liquid returns to the washer in a continuous cyclic process.

A convenient rate of pumping is such that v the liquid in the washer is changed about 6 times during the washing operation. A suspension of filter aid is run into the dirty spirit line between the washer and the pump. The filter aid may be highlydivided porous cellular silica, weighing 12 pounds or less per cubic foot, as described in the specification of application Patent No. 1,704,60 above mentioned. This is conveniently suspended in the cleaning fluid and run in at either a regular or varying rate, preferaby from a tank fitted with an agitator, in su cient quantity to maintain free and clear filtration. A convenient quantity is usually 3 per cent or less on the weight of goods to be cleaned of filter aid distributed over the washing operation, which ordinarily takes 10 to 20 minutes according to the nature of the articles being treated.

At the end of the process the fluid in the machine is run to a tank for re-use, and the goods are hydroed and removed. The pump and press are preferably connected to a second washer in the meantime, or, if further washing is not immediately proceeded with, the discharge from the press is recirculated to it in such a manner as to maintain a pressure across the filter surface, so as to maintain the deposit in the best condition. Fresh cleaning fluid is added as required. 111

other known types of washing machine the work is hydroed in a separate machine after washing is completed.

We claim- .1. A process for dry-cleaning, laundry washing, wool-scourin and the like comprising adding soap 0 high solubility and emulsifying power having little tendency to disassociate toa cleanin fluid in a washing machine, washing t e soiled articles therein, withdrawing the soiled cleaning fluid and soap from the washing machine, adding a filter aid to the soiled fluid, passing the soiled fluid with the filter aid in suspension therein to a filter, and there filtering the soiled liquid.

2. A process for dry-cleaning, laundrywashing, wool-scouring and the like comprising adding soap of high solubility and emulsifying power having little tendency to disassociate to a cleaning fluid in a washing machine, washing the soiled articles therein, withdrawing the soiled cleaning fluid and soap from the washing machine, adding a filter aid to the soiled fluid, passing the soiled fluid with the filter aid in suspension therein to a filter, there filtering the soiled cleaning fluid and soap, and returning the filtered cleaning fluid and soap to the washing machine in a continuous cyclic process.

3. A process for dry-cleaning, laundrywashing, wool scouring, and the like, comprising adding to a cleaning fluid in a washing machine a soap of high solubility and emulsifying power having little tend.- ency to disassociate, washing the soiled articles therein, passing the soiled cleaning fluid and soap from the washing machine to a filter, adsorbing dirt and moisture from the soiled fluid between the Washing machine and the filter by adding finely divided.cellular silica of low specific gravity thereto, passing the silica in suspension to the filter, there filtering the soiled liquid and returning the filtered liquid to the washing machine in a continuous cyclic process. A

In testimony whereof we have signed our names to this specification.

ARTHUR EDWARD HATFIELD.

EUSTAOE ALEXANDER ALLIOTT. 

